Question: What particle radiation stars with the letter c?
Paraphrase: What molecule radiation stars with the letter c?
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q945733 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'c')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: cosmic ray, cosmic ray